A Philadelphia man is charged with stabbing a pregnant woman and her unborn child to death inside her Elkins Park apartment last month, the Montgomery County DA's office announced on Tuesday.

Tristian Jones, 35, of the East Germantown area, is charged with murdering 31-year-old Ebony White, who was 7 and 1/2 months pregnant, in front of her two children, aged 7 and 12.

Now he faces charges both for her murder and murder of her unborn child, the DA's office said.

"Domestic violence and intimate partner violence like this senseless killing is all too often a hidden crime until its too late and police arrive to investigate a murder," Montgomery County DA Kevin Steele said in a statement. "This attack and murder of a mother and her unborn child happened while her two young children were in the apartment. They could hear their mother being attacked and stabbed to death."

Cheltenham Township police responded to White's apartment on Mather Way in Elkins Park around 3:20 a.m. on Feb. 19. They had received a call from her 12-year-old daughter, calling from inside the apartment bathroom.

The 12-year-old later told investigators she had seen a man she called "Mr. Tristian" at the doorway to her mother's room. During an interview with child advocates and prosecutors, she said "she heard screaming and went into her mother's bedroom … [and] saw the male stabbing her mother."

The daughter said she begged the attacker to stop. "She screamed at the male to stop hurting her mother and the male lunged at her with the knife in his hand. [She] retreated to the bathroom where she called 911," a police report stated.

Jones was quickly identified but denied any involvement in the murder to police. But witnesses and text messages indicated he and White had been having difficulties over her pregnancy, which he had not told his wife about.

Witnesses said Jones had previously urged White to drink a "white, foamy liquid," allegedly telling her, "Drink it if you love me… it will be good for you and the baby." When she refused, he grew angry.

He also allegedly at one point gave her a tampered-with Pepsi, which he claimed he had diluted with water to reduce her caffeine.

In lengthy text message conversations from Jones' phone to White's the day before the murder, he discusses watching a broadcast by Watchtower and his thoughts on "fornication."

"I still want to do what's right. And I still recognize that fornication is a sin. I haven't changed my viewpoints on fornication," he texted her just nine hours before her death. "I committed a sin. And I can't let the kids think that part was okay … I don't want any of the kids yours included thinking sex before marriage."

Around 3:23 and 3:25 a.m. after White had been stabbed Jones, allegedly sent two more texts: "Just woke back up. You up? … Just thinking. I really hope all this ends well."

But investigators also said Jones was spotted on surveillance cameras wearing outfits matching the description of the attacker given by White's daughter.

Jones was jailed after being arraigned on Monday and will have a preliminary hearing on March 29 in Montgomery County Court.